371 research outputs found

    Inverse Modelling to Obtain Head Movement Controller Signal

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    Experimentally obtained dynamics of time-optimal, horizontal head rotations have previously been simulated by a sixth order, nonlinear model driven by rectangular control signals. Electromyography (EMG) recordings have spects which differ in detail from the theoretical rectangular pulsed control signal. Control signals for time-optimal as well as sub-optimal horizontal head rotations were obtained by means of an inverse modelling procedures. With experimentally measured dynamical data serving as the input, this procedure inverts the model to produce the neurological control signals driving muscles and plant. The relationships between these controller signals, and EMG records should contribute to the understanding of the neurological control of movements

    Telerobotics: A simulation facility for university research

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    An experimental telerobotics (TR) simulation suitable for studying human operator (H.O.) performance is described. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. A number of control modes could be compared in this TR simulation, including displacement, rate and acceleratory control using position and force joysticks. A homeomorphic controller turned out to be no better than joysticks; the adaptive properties of the H.O. can apparently permit quite good control over a variety of controller configurations and control modes. Training by optimal control example seemed helpful in preliminary experiments. An introduced communication delay was found to produce decrease in performance. In considerable part, this difficulty could be compensated for by preview control information. That neurological control of normal human movement contains a data period of 0.2 second may relate to this robustness of H.O. control to delay. The Ames-Berkeley enhanced perspective display was utilized in conjunction with an experimental helmet mounted display system (HMD) that provided stereoscopic enhanced views

    Association between miscarriage and cardiovascular disease in a Scottish cohort

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    Funding This work was supported by a grant from the ‘Merel Foundation’, the Netherlands. The AMND receives support from the University of Aberdeen.Peer reviewedPostprin

    Association between contemporary hormonal contraception and ovarian cancer in women of reproductive age in Denmark : prospective, nationwide cohort study

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    Supported by a grant (11645) from the Novo Nordisk Foundation. The funder had no role in the study design; in the collection, analysis and interpretation of data, in the writing of the paper or in the decision to submit the paper for publication.Peer reviewedPublisher PD

    Hormonal contraceptive use and risk of pancreatic cancer : A cohort study among premenopausal women

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    Drs. Mørch and Lidegaard were supported by a grant (No 11645) from the Novo Nordisk Foundation. The funder had no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the paper; or in the decision to submit the paper for publication. Correction: Hormonal contraceptive use and risk of pancreatic cancer—A cohort study among premenopausal women; Sedrah Arif Butt, Øjvind Lidegaard, Charlotte Skovlund, Philip C. Hannaford, Lisa Iversen, Shona Fielding, Lina Steinrud Mørch; PLOS, Published: March 28, 2019, https://doi.org/10.1371/journal.pone.0214771Peer reviewedPublisher PD

    Enhancement factor for the electron electric dipole moment in francium and gold atoms

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    If electrons had an electric dipole moment (EDM) they would induce EDMs of atoms. The ratio of the atomic EDM to the electron EDM for a particular atom is called the enhancement factor, R. We calculate the enhancement factor for the francium and gold atoms, with the results 910 plus/minus 5% for Fr and 260 plus/minus 15% for Au. The large values of these enhancement factors make these atoms attractive for electron EDM measurements, and hence the search for time-reversal invariance violation.Comment: 6 pages, no figures, uses RevTex, reference adde

    Optogalvanic Spectroscopy of Metastable States in Yb^{+}

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    The metastable ^{2}F_{7/2} and ^{2}D_{3/2} states of Yb^{+} are of interest for applications in metrology and quantum information and also act as dark states in laser cooling. These metastable states are commonly repumped to the ground state via the 638.6 nm ^{2}F_{7/2} -- ^{1}D[5/2]_{5/2} and 935.2 nm ^{2}D_{3/2} -- ^{3}D[3/2]_{1/2} transitions. We have performed optogalvanic spectroscopy of these transitions in Yb^{+} ions generated in a discharge. We measure the pressure broadening coefficient for the 638.6 nm transition to be 70 \pm 10 MHz mbar^{-1}. We place an upper bound of 375 MHz/nucleon on the 638.6 nm isotope splitting and show that our observations are consistent with theory for the hyperfine splitting. Our measurements of the 935.2 nm transition extend those made by Sugiyama et al, showing well-resolved isotope and hyperfine splitting. We obtain high signal to noise, sufficient for laser stabilisation applications.Comment: 8 pages, 5 figure

    Public attitudes towards pricing policies to change health-related behaviours: a UK focus group study.

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    BACKGROUND: Evidence supports the use of pricing interventions in achieving healthier behaviour at population level. The public acceptability of this strategy continues to be debated throughout Europe, Australasia and USA. We examined public attitudes towards, and beliefs about the acceptability of pricing policies to change health-related behaviours in the UK. The study explores what underlies ideas of acceptability, and in particular those values and beliefs that potentially compete with the evidence presented by policy-makers. METHODS: Twelve focus group discussions were held in the London area using a common protocol with visual and textual stimuli. Over 300,000 words of verbatim transcript were inductively coded and analyzed, and themes extracted using a constant comparative method. RESULTS: Attitudes towards pricing policies to change three behaviours (smoking, and excessive consumption of alcohol and food) to improve health outcomes, were unfavourable and acceptability was low. Three sets of beliefs appeared to underpin these attitudes: (i) pricing makes no difference to behaviour; (ii) government raises prices to generate income, not to achieve healthier behaviour and (iii) government is not trustworthy. These beliefs were evident in discussions of all types of health-related behaviour. CONCLUSIONS: The low acceptability of pricing interventions to achieve healthier behaviours in populations was linked among these responders to a set of beliefs indicating low trust in government. Acceptability might be increased if evidence regarding effectiveness came from trusted sources seen as independent of government and was supported by public involvement and hypothecated taxation.The study was funded by the UK Department of Health Policy Research Programme (Policy Research Unit in Behaviour and Health [PR-UN-0409-10109]). The Department of Health had no role in the study design, data collection, analysis, or interpretation. The research was conducted independently of the funders, and the views expressed in this paper are those of the authors and not necessarily those of the Department of Health in England.This is the final version of the article. It was first available from Oxford University Press at http://dx.doi.org/10.1093/eurpub/ckv07
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